crypto: api - Do not wait for tests during registration

As registration is usually carried out during module init, this
is a context where as little work as possible should be carried
out.  Testing may trigger module loads of underlying components,
which could even lead back to the module that is registering at
the moment.  This may lead to dead-locks outside of the Crypto API.

Avoid this by not waiting for the tests to complete.  They will
be scheduled but completion will be asynchronous.  Any users will
still wait for completion.

Reported-by: Russell King <linux@armlinux.org.uk>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 12 insertions, 11 deletions

diff --git a/crypto/algapi.c b/crypto/algapi.c
index d2ccc1289f92..74e2261c184c 100644
--- a/crypto/algapi.c
+++ b/crypto/algapi.c
@@ -366,7 +366,8 @@ void crypto_alg_tested(const char *name, int err)
 	}
 
 	pr_err("alg: Unexpected test result for %s: %d\n", name, err);
-	goto unlock;
+	up_write(&crypto_alg_sem);
+	return;
 
 found:
 	q->cra_flags |= CRYPTO_ALG_DEAD;
@@ -387,11 +388,12 @@ found:
 	crypto_alg_finish_registration(alg, &list);
 
 complete:
+	list_del_init(&test->alg.cra_list);
 	complete_all(&test->completion);
 
-unlock:
 	up_write(&crypto_alg_sem);
 
+	crypto_alg_put(&test->alg);
 	crypto_remove_final(&list);
 }
 EXPORT_SYMBOL_GPL(crypto_alg_tested);
@@ -412,7 +414,6 @@ int crypto_register_alg(struct crypto_alg *alg)
 {
 	struct crypto_larval *larval;
 	LIST_HEAD(algs_to_put);
-	bool test_started = false;
 	int err;
 
 	alg->cra_flags &= ~CRYPTO_ALG_DEAD;
@@ -423,15 +424,16 @@ int crypto_register_alg(struct crypto_alg *alg)
 	down_write(&crypto_alg_sem);
 	larval = __crypto_register_alg(alg, &algs_to_put);
 	if (!IS_ERR_OR_NULL(larval)) {
-		test_started = crypto_boot_test_finished();
+		bool test_started = crypto_boot_test_finished();
+
 		larval->test_started = test_started;
+		if (test_started)
+			crypto_schedule_test(larval);
 	}
 	up_write(&crypto_alg_sem);
 
 	if (IS_ERR(larval))
 		return PTR_ERR(larval);
-	if (test_started)
-		crypto_wait_for_test(larval);
 	crypto_remove_final(&algs_to_put);
 	return 0;
 }
@@ -646,8 +648,10 @@ int crypto_register_instance(struct crypto_template *tmpl,
 	larval = __crypto_register_alg(&inst->alg, &algs_to_put);
 	if (IS_ERR(larval))
 		goto unlock;
-	else if (larval)
+	else if (larval) {
 		larval->test_started = true;
+		crypto_schedule_test(larval);
+	}
 
 	hlist_add_head(&inst->list, &tmpl->instances);
 	inst->tmpl = tmpl;
@@ -657,8 +661,6 @@ unlock:
 
 	if (IS_ERR(larval))
 		return PTR_ERR(larval);
-	if (larval)
-		crypto_wait_for_test(larval);
 	crypto_remove_final(&algs_to_put);
 	return 0;
 }
@@ -1042,6 +1044,7 @@ static void __init crypto_start_tests(void)
 
 			l->test_started = true;
 			larval = l;
+			crypto_schedule_test(larval);
 			break;
 		}
 
@@ -1049,8 +1052,6 @@ static void __init crypto_start_tests(void)
 
 		if (!larval)
 			break;
-
-		crypto_wait_for_test(larval);
 	}
 
 	set_crypto_boot_test_finished();